Rope clamp



1967 D. B. MORITZ 3,357,066

Y I ROPE CLAMP Filed Dec. 27, 1965 jizverz/far Dana/M ,5 M02 6 Zz United States Patent 3,357,066 ROPE CLAMP Donald B. Moritz, Arlington Heights, 111., assignor, by

mesne assignments, to Bliss & Laughlin Industries, Incorporated, Oak Brook, 111., a corporation of Delaware Filed Dec. 27, 1965, Ser. No. 516,238 8 Claims. (Cl. 24-125) ABSTRACT OF THE DISCLOSURE A rope clamp for helically twisted strands of filaments which engages the rope over one full turn and within that length laterally offsets the rope approximately its thickness with a double reverse bend or oxbow in which each strand or filament is disposed in paths of identical lengths so that all strands entering and leaving the clamp are subjected to the same longitudinal stress in the clamp.

The present invention relates to mechanical clamps for use in the field and otherwise with the fastening or securing of ropes wound of helically twisted clusters or strands of filaments of metal, plastic or fibers, or any combination thereof, Whether wound with a regular lay or a lang lay, and particularly with the former which constitutes the least flexible of the two lays, where the strands are laid in one helical direction and the filaments in the strands are laid in the opposite helical direction with the result that the filaments align themselves longitudinally of the rope on the outer surface thereof.

Furthermore, a clamp embodying invention is capable of use with rope made up of different metals such as aluminum and copper, as well as ferrous metals which include plow steel, such rope generally embodying a core of compressed fibrous material of less hardness than that of the outer strands.

Clamps for rope (small size) or cable (large size), are of generally two types; namely offset and compressive. The offset type have heretofore been provided which flex the rope over a distance greater than three diameters of the rope. The compressive type is generally recognized as having radial forces applied at circumferentially .spaced points and generally consist of one or more transverse clamping stations of; (1) a length less than one rope diameter such as occurs with U-bolt clamps or set screws; or, (2) a length exceeding five or six diameters with individual clamp bolts spaced longitudinally of the wire. In the latter, most of the clamping areas are cylindrical, or, a unilateral V groove in one of the elements, or, a counter die type surface that will only take one particular lay both as to size and length.

The present invention comprises a clamp that is in engagement with approximately a six-to-seven diameter length of the rope approximately three diameters of which are devoted to offset for a novel purpose and relationship herein described while the remainder is divided equally on opposite sides thereof. The total length basically is substantially the length of the lead, e.g. a 360 strand helix.

More particularly the invention is characterized by an oxbow or double reverse bend offset from a straight line in which the symmetrical U-portion thereof is induced and clamped between two cooperating members having a common or base plane of engagement, one a stud which may have a frusto-conical shape having an included angle of 10 and defining major and minor diameters with rounded terminal edges which assists in molding the part and also in bodily offsetting a portion of a rope of an intermediate diameter into a cooperating recess upon the other member whose walls have the same taper as the stud. The width of the recess at the base plane is substantially the width of the stud and its length is approxi- 3,357,966 Patented Dec. 12, 1967 mately three times its Width, e.g. approximately three times the rope diameter. The height of the stud from the base plane is approximately 4 of its major diameter and the depth of the recess is approximately one and one-half times its width. At opposite ends of the recess the two elements have facing grooves compositely defining a regular polygonal figure sectionally whose minor dimension is less than the rope diameter, or preferably is the minor width of the recess at its bottom.

It is one of the objects of the invention to impose a clamped oxbow configuration upon the rope whose U- shaped contour has an internal diameter approximately equal to the diameter of the rope, or approximately onesixth of one complete helical turn of one of the strands and thus the U-bend portion is completed for the rope in onehalf of a complete helical turn, so that half the strands from one side of the bend are subjected to the same strains and distortion as the other half of strands from the other side of the bend portion whereby an equalization factor is provided throughout the bend. In brief, each strand in the bend starts on one side of the rope and ends up on the other side, all traversing the same distance in the bend.

It is a further object of the invention to impose upon the aligned sections of the rope contiguous to the equalizing U-bend a regular non-circular sectional con-figuration which compressively preserves equalized tensional forces for all strands and does not impose a concentration of tensional forces upon any particular strands, and further also imposes uniform reaction forces on all strands which require a changing of its sectional shape if the rope tends to slip at all.

A further object resides in the relationship that along with equalization of the working tensile strain upon all strands, the associated clamping relationship can be extremely heavy for all purposes but such is also equalized over the length of the engagement so that no strands are weakened by buckling, nicking or abrasion.

The present invention further contemplates the formation of a terminal loop for a straight-away pull of the rope in which the secured rope portions closing the loop are laterally within a rope diameter of each other in a direction facing the tensile load and are equally flexed divergently in the direction facing the anchorage. The invention is equally applicable to also anchoring adjacent cable portions under tension against relative shifting whether the portions be integral parts of the same rope or portions of separate ropes in a network.

The invention is characterized by two identical members to reduce inventory items and are either cast or forged of a mild steel or malleable iron or other materials, depending upon any codes that may be applicable to certain classes or uses of rope clamps, and the rope offsetting elements are located where they are between two clamping bolts so that the clamping force is fulcrumed crosswise of the rope portions for equalization of clamping pressures on opposite sides thereof whereby the assembled members may be of an external spherical shape without corners or edges to injure hand-s or elements coming in contact therewith. The members may be plated if desired without adversely affecting the clamping relationship. Moreover, the convex curve of the body proximate to the ropes permit useful divergence of the rope portions for close loops having thimbles in them.

Further objects of the invention is to provide a rope clamp which has an effective holding power approaching that of the rope; which when removed permits the strands and filaments to resume original form without damage; a two-part separable cable clamp which is extremely compact and which involves no excess metal over that required in the immediate vicinity of the cable portions undergoing clamping; one. which consumes less over-all space than conventional clamps designed for the same purpose; one which is comprised of only two principal parts, both of which are identical, thereby contributing to economy of manufacture; one which contains no relatively moving hinged or sliding parts and which therefore cannot get out of order; one which is rugged and durable and which, therefore, will withstand rough usage; one which is reusable in different installations; one which is attractive in its appearance and pleasing in its design; and one which, otherwise, is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production and development of the present invention.

Numerous other objects and advantages of the invention, not at this time enumerated, will readily suggest themselves as the nature of the invention is better understood.

In the accompanying single sheet of drawings forming a part of this specification, a preferred illustrative embodiment of the invention has been shown.

In these drawings:

FIG. 1 is a plan view, partly in section of a rope clamp embodying the principles of the present invention and showing the same assembled upon a length of rope for the purpose of providing a terminal looped end;

FIG. 2 is an exploded perspective view of the rope clamp;

FIG. 3 is an inside plan view of one of two identical clamp parts employed in connection with the present invention;

FIG. 4 is an exploded sectional view taken centrally and longitudinally through the rope clamp;

FIG. 5 is an enlarged sectional view taken substantially on the line 55 of FIG. 1; and

FIG. 6 is an end view of the clamp.

Referring now to the drawings in detail, and in particular to FIG. 1, a rope clamp constructed according to the present invention has been designated in its entirety at 10 and is shown as being operatively applied to the end region of a length of twisted strand rope 12 of regular lay to provide a terminal loop 14. The loop is narrowed at its turn to save drawing space as an example of a continuous use of the rope although it will be appreciated that in practice a thimble would be used at the curve. To produce the looped end 14, the rope is provided with a reverse or re-entrant bend 16 which establishes a pair of parallel portions 18 closely spaced Where they pass through the clamp 10 and are secured thereby in a manner that will be made clear presently. The rope clamp 10 comprises two principal parts 20 and 22 which are of identical construction and therefore a description of one will sufiice for both. Moreover, the clamp 10 further includes two clamping bolts 24 by means of which the two parts can be assembled upon the rope 12 in the field by a hand tool in full clamping relationship. Each part 20 or 22, as the case may be, is in the form of a generally semi-spherical shape with adequate stock for strength and presenting a planar or flat circular inner face 25 which is interrupted by a pair of closely spaced linearly straight parallel V-grooves 26 and 28, the inclined walls of which preferably extend at right angles to each other to provide compositely a minor dimension less than the diameter of the rope 12. The two V-grooves in each part are slightly spaced laterally by means of a narrow fiat ridge portion or land area 30 to insure flat seating surfaces when the parts are assembled and drawn tight if an endeavor is made to use them with too small a rope. The V-grooves 26 and 28 are disposed inwardly from two diametrically opposed points so that they extend in secant fashion across the flat face and establish two flat land areas 32 and 34 in addition to the land area afforded by the ridge portion 30. The other side 35 of the casting is of a rounded convex configuration.

A post or stud 36 tapering at an an included angle of 10 projects outwardly from the bottom of the V- groove 26 in the medial region of the latter and extends well forwardly of the general plane of the face 25 a distance approximately /1 of its major diameter. As best seen in FIG. 2 the V-groove 28 is provided with a centrally located relatively deep elongated recess 38, correspondingly tapered and of a length approximately three time the major diameter of the stud. Each groove receives a stud therein to a depth leaving a space approximately the diameter of the rope.

A threaded bore 40 extends through each part 20 and 22 and opens onto the land area 34 for the threaded reception therein of the shank portion 23 of one of the two clamping bolts 24. A cylindrical bore 42 similarly extends through each part and opens onto the land area 32. This later bore is outwardly enlarged at 44 for reception therein of the head 27 of the bolt in recessed relationship.

In the operation of the rope clamp 10, the clamping bolts 24 are removed from their anchorage in their respective parts 20 and 22 to free the two assembled parts from each other. Thereafter, the two parallel rope portions 18 which are to be clamped are loosely disposed in the adjacent grooves 26 and 28, after which the mating parts 20 and 22 are juxtapositioned in the manner illustrated in FIG. 2 so that each post 36 on one part opposes the recess 38 of the other part while the groove 26 of each part opposes the groove 28 of the other part. The two clamping bolts 24 are then passed through the cylindrical bores 42 and the shank portions thereof are threaded into the threaded bores 40 to initially draw the two parts 20 and 22 toward each other while the rope portions are held bottomed in the grooves having the recesses therein. Thereafter the bolts are tool tightened into clamping relationship with respect to the two parallel rope portions 18. During this bolt-tightening operation, the distal end of each stud 36 bears endwise laterally against the adjacent rope portion 18 and flexes the medial region thereof inwardly into the respective recesses 38, thus drawing a limited amount of rope material inwardly of the circular confines of the clamp 10 as a whole and causing the rope to bow deeply into the recesses while the opposed pairs of V-grooves 26, 28 maintain straight the adjacent portions of the rope within the confines of the clamp. Continued tightening of the bolts 24 ultimately causes the linearly straight sections of the rope on opposite sides of the mating post and sockets to be radially offset to assume a square sectional configuration securely clamped between the opposed pairs of V-grooves while the lateral offset portion 50 (FIG. 5) is established in each rope portion 12 which is extremely effective in snubbing and frictionally restraining the rope portions 12 against endwise shifting under the influence of tensile forces exerted on the rope on either side of the clamp.

It is to be noted at this point that the present rope clamp 10 is so designed that no sharp corners or teeth are present to damage the individual filaments of a twisted strand rope, and also that no localized regions of extreme inward pressure or concentrated tensions are applied to the individual filaments or strands of the rope at any point within the confines of the clamp. For instance, only one-half of the full turn of a strand is forced laterally so that with the completion of the bend from the straight to the straight portions of the rope each strand starts on one side of the rope and ends diametrically on the opposite side of the rope, thereby providing equal lengths in the bend as the bend is formed.

Depending upon possible variation in the diameters of the particular ropes undergoing clamping, the V-grooves 26 and 28 may or may not exert full clamping pressure upon the rope when the two opposed planar faces 25 of the parts 20 and 22 are in face-to-face contiguity so long as the rope straight portions are held straight. Even a very light clamping pressure of the inclined walls of the V- grooves on the rope will be adequate to prevent longitudinal shifting of the rope portions 12 in most applications due to the tortuous double reverse snubbing paths provided for these rope portions through the clamp. On the other hand, it is not essential that the planar faces 25 be in contact with each other inasmuch as under a condition where a relatively oversize diameter cable is undergoing clamping, these opposed faces 25 may remain slightly spaced from each other when the clamping bolts 24 are fully tightened since the clamping pressure is evenly balanced on opposite sides of two clamping bolts disposed crosswise to and on opposite sides of the clamped rope portions.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. For example, whereas the present rope clamp has been shown and described as being applied to a single cable length 12 having parallel portions 18 which are engaged by the clamp 10, obviously the clamp may be employed for clamping parallel portions of two separate ropes in their fixed relationship. Thus, the clamp 10 may be found useful as a rope or wire connector, as for example in connection with high voltage copper or other transmission lines. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

What is claimed is:

1. A two-part separable rope clamp for fixedly anchoring a twisted rope portion over the length of one full twist thereof, said clamp comprising two juxtapositioned clamping parts adapted to be driven toward each other to clamp the rope portion therebetween, said clamping parts having opposed planar faces, each of said faces being formed with a lineally straight V-groove therein defining a 90 included angle extending thereacross, each groove of each face registering with the groove of the other face to provide a polygonal configuration whose minimal dimension is a little less than the diameter of the rope portion, the registering grooves being adapted for reception therein and therebetween of the rope portion, a rope-engaging tapered stud projecting upwardly from the medial region of the one groove and having a height above said planar face approximately three-fourths of the rope diameter, the other groove being provided with a medially disposed recess of a length three times the diameter of the rope and of a depth greater than the height of the stud by substantially the diameter of the rope said stud being designed for entry into the recess of said other groove when the parts are drawn inwardly toward each other, and means for driving said parts inwardly toward each other.

2. A two-part separable rope clamp for fixedly anchoring two rope portions in closely spaced parallelism, said clamp comprising two substantially identical juxtapositioned clamping parts adapted to be drawn inwardly into contact with each other to clamp the rope portions therebetween, said clamping parts having opposed planar faces, each of said faces being formed with a pair of lineally straight parallel grooves therein extending completely thereacross, each groove of each face registering with a non-corresponding groove of the other face to form tubular openings whose minimum cross sectional dimension is appreciably less than the diameter of the rope portions, the registering pairs of grooves being adapted for reception therein and therebetween of the respective rope portions, one groove of each registering pair being provided with a medially disposed recess portion of a depth approximately twice the depth of the groove from the bottom of the groove and a lenth of approximately two and a half times the thickness of the rope, a rope engaging stud projecting upwardly from the bottom of the other groove of such registering pair approximately twice the height of the other groove and designed for entry into the recess of said one groove when the parts are drawn inwardly toward each other, and means for drawing said parts inwardly toward each other.

3. A two-part separable rope clamp as set forth in claim 2, wherein each stud and each socket is equally spaced from the opposite ends of their associated groove.

4. A two-part separable rope clamp as set forth in claim 2, wherein said planar faces are of circular outline.

5. A two-part separable rope clamp as set forth in claim 2, wherein said planar faces are circular in outline, and wherein the two grooves in each of said planar faces are substantially contiguous.

6. A two-part separable rope clamp as set forth in claim 2, wherein said planar faces are circular in outline, wherein the grooves in each of said planar faces are substantially contiguous, and wherein the means for drawing said parts inwardly toward each other comprises a pair of clamping bolts on opposite sides of the substantially contiguous grooves respectively, each of said bolts projecting loosely through one of the parts and exerting a reaction force on the other part.

7. A two-part separable rope clamp as set forth in claim 6, wherein each clamping bolt has an enlarged head portion seated against one of the parts and its shank portion threadedly received in the other part in a plane in common with the axes of said studs.

8. A two-part separable rope clamp as set forth in claim 7, wherein the remote sides of said clamping parts are of convex configuration, and wherein the space between the stud and the end and bottom walls of said recess in clamped relationship is substantially the diameter of the rope.

References Cited UNITED STATES PATENTS 508,687 11/1893 Duggan.

538,075 4/1895 Herrberg 24-135 1,767,432 6/1930 Caulkins 24135 2,039,669 5/1936 Tenney 339265 X 2,271,270 1/ 1942 McLearn 24-125 2,426,859 9/1947 Case 24-125 FOREIGN PATENTS 948,529 9/ 6 Germany.

182,706 2/ 193 6 Switzerland.

BERNARD A. GELAK, Primary Examiner, 

1. A TWO-PART SEPARABLE ROPE CLAMP FOR FIXEDLY ANCHORING A TWISTED ROPE PORTION OVER THE LENGTH OF ONE FULL TWIST THEREOF, SAID CLAMP COMPRISING TWO JUXTAPOSITIONED CLAMPING PARTS ADAPTED TO BE DRIVEN TOWARD EACH OTHER TO CLAMP THE ROPE PORTION THEREBETWEEN, SAID CLAMPING PARTS HAVING OPPOSED PLANAR FACES, EACH OF SAID FACES BEING FORMED WITH A LINEALLY STRAIGHT V-GROOVE THEREIN DEFINING A 90* INCLUDED ANGLE EXTENDING THEREACROSS, EACH GROOVE OF EACH FACE REGISTERING WITH THE GROOVE OF THE OTHER FACE TO PROVIDE A POLYGONAL CONFIGURATION WHOSE MINIMAL DIMENSION IS A LITTLE LESS THAN THE DIAMETER OF THE ROPE PORTION, THE REGISTERING GROOVES BEING ADAPTED FOR RECEPTION THEREIN AND THEREBETWEEN OF THE ROPE PORTION, A ROPE-ENGAGING TAPERED STUD PROJECTING UPWARDLY FROM THE MEDIAL REGION OF THE ONE GROOVE AND HAVING A HEIGHT ABOVE SAID PLANAR FACE APPROXIMATELY THREE-FOURTHS OF THE ROPE DIAMETER, THE OTHER GROOVE BEING PPROVIDED WITH A MEDIALLY DISPOSED RECESS OF A LENGTH THREE TIMES THE DIAMETER OF THE ROPE AND OF A DEPTH GREATER THAN THE HEIGHT OF THE STUD BY SUBSTANTIALLY THE DIAMETER OF THE ROPE SAID STUD BEING DESIGNED FOR ENTRY TO THE RECESS OF SAID OTHER GROOVE WHEN THE PARTS ARE DRAWN INWARDLY TOWARD EACH OTHER, AND MEANS FOR DRIVING SAID PARTS INWARDLY TOWARD EACH OTHER. 